Controller for camera

ABSTRACT

A controller for a camera is provided with a first zoom signal output device operatively associated with the half depressing operation of a release operation member and outputting a first zoom signal for directing a photographing lens to a focal length preset on the camera, a second zoom signal output device outputting a second zoom signal for arbitrarily varying the focal length of the photographing lens by a manual operation, a drive device responsive to the first or second zoom signal to electrically drive the photographing lens and effect zooming, a mode command device for commanding the setting and release of an auto focal length mode in which the focal length of the photographing lens is changed with the first zoom signal, by a manual operation, and a control device for operating the first zoom signal output device by the first half depressing operation of the release operation member when the auto focal length mode is set, and releasing the auto focal length mode when the second zoom signal is output during the time from after the half depressing operation is released until the next shutter release, and thereafter inhibiting the operation of the first zoom signal output device until the shutter release is effected even if the half depressing operation is done.

This is a continuation of application Ser. No. 447,575 filed Dec. 7,1989 (now abandoned), which is a continuation-in-part of applicationSer. No. 301,050 filed Jan. 24, 1989 (now U.S. Pat. No. 4,896,177 issuedJan. 23, 1990).

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a controller for a camera.

2. Related Background Art

An electric zoom camera capable of accomplishing so-called givenmagnification photography in which an object is photographed always at apredetermined size irrespective of the object distance by operating agiven magnification setting button or the like has been proposed.

In the camera of this type, a plurality of magnification tables in whichthe object distance and the focal length are made to correspond to eachother in advance are stored in CPU to change the focal length of thephotographing lens in conformity with the object distance and make givenmagnification photography possible. By half depressing a release buttonafter the given magnification photographing mode is set by the operationof the given magnification setting button, one of the tables is selectedin the camera, and from that table, for example, a focal lengthcorresponding to the object distance obtained by a distance measurementcircuit is selected and set and the photographing lens is automaticallydriven to that focal length, and photographing is effected by the halfdepressing operation of the release button. In such magnificationtables, the ratio of the object distance to the focal length, i.e., thephotograph magnification is always made constant so that for example,the bust or the whole of a person is photographed always at the samesize, and the photographer can also select the photograph magnificationby the operation of an operating button or the like.

Also known is a camera in which a desired focal length is input inadvance to the camera by a manual operation and when the half depressionoperation of a release button is thereafter effected, a photographinglens is driven at a stroke to the input focal length.

However, in such a camera, when for example, a mode in which givenmagnification photography is effected is set, the camera automaticallysets the focal length of the photographing lens and effects zooming, andtherefore it is sometimes the case that the composition is notsatisfactory to the photographer, and this is disadvantageous.

Also known is a camera in which as disclosed, for example, in JapanesePatent Publication No. 51-27577, the focal length of a photographinglens such as a zoom lens is automatically adjusted so that apredetermined photograph magnification is always provided even if thephotographing distance varies for the same object.

Now, in a photographing lens capable of photographing at a plurality offocal lengths, such as a zoom lens, the full open aperture stop valuediffers with a variation in the focal length and therefore, for example,where the zoom lens is driven to the telephoto side, in spite of thefact that before the driving, it is not necessary to cause a flashdevice to emit light for the same composition, the full open aperturestop value becomes greater (e.g., F2→F5.6) after the driving and thenecessity of light emission sometimes arises. Hereinafter, the lightemission by the flash device will be referred to as flash lightemission.

In the conventional camera, after the zoom lens is driven to apredetermined focal length, calculation of an exposure value is effectedby the use of a full open aperture stop value conforming to that focallength. Accordingly, whether flash light emission is necessary after thedriving of the photographing lens can be known, and when flash lightemission is necessary, charging is started at that point of time. Sincephotographing cannot be accomplished until charging is complete, inspite of the lens having been set to the predetermined focal length,this delay may displease to the photographer.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a zooming controllerfor a camera capable of photographing at an intended focal length evenduring the setting of the mode as described above.

It is another object of the present invention to provide an operationcontroller for a camera capable of photographing on the spot after thefocal length is changed.

Describing the present invention with reference to FIG. 1A of theaccompanying drawings, a zooming controller is provided with first zoomsignal output means 102 operatively associated with the half depressingoperation of a release operation member 101 and outputting a first zoomsignal for directing a photographing lens LE to a focal length preset onthe camera second zoom signal output means 103 outputting a second zoomsignal for arbitrarily varying the focal length of the photographinglens LE by a manual operation, drive means 104 responsive to the firstor second zoom signal to electrically drive the photographing lens LEand effect zooming, mode command means 105 for commanding the settingand release of an auto focal length mode in which the focal length ofthe photographing lens LE is changed with the first zoom signal, by amanual operation, and control means 106 for operating the first zoomsignal output means by the first half depressing operation of therelease operation member 101 when the auto focal length mode is set, andreleasing the auto focal length mode when the second zoom signal isoutput during the time from after the half depressing operation isreleased until the next shutter release, and thereafter unhibiting theoperation of the first zoom signal output means 102 until the shutterrelease is effected even if the half depressing operation is done.

Also, describing the present invention with reference to FIG. 1B of theaccompanying drawings a zooming controller has the above-described firstzoom signal output means 102, the above-described second zoom signaloutput means 103, the above-described drive means 104 and theabove-described mode command means 105, and the control means 206 whichfunctions as follows: it operates the first zoom signal output means 102by the first half depressing operation of the release operation member101 when the auto focal length mode is set, and releases the auto focallength mode in response to the drive means 104 being operated by thefirst zoom signal resulting from said operation, and thereafter inhibitsthe operation of the first zoom signal output means 102 until the autofocal length mode is re-set even if the half depressing operation isagain performed, and operates the drive means 104 when the second zoomsignal is output.

Further, describing the present invention with reference to FIG. 1C ofthe accompanying drawings a zooming controller has the above-describedfirst zoom signal output means 102, the above-described second zoomsignal output means 103, the above-described drive means 104 and theabove-described mode command means 105, and the control means 306 whichfunctions as follows: it operates the first zoom signal output means 102by the first half depressing operation of the release operation member101 when the auto focal length mode is set, and releases the auto focallength mode in response to said half depressing operation being releasedwithout shutter release being effected, and thereafter inhibits theoperation of the first zoom signal output means 102 until the auto focallength mode is re-set even if the half depressing operation is againperformed, and operates the drive means 104 when the second zoom signalis output.

(1) The apparatus according to the invention of FIG. 1A:

When the auto focal length mode is set, the control means 106 operatesthe first zoom signal output means 102 by the first half depressingoperation of the release operation member 101 and effects zooming at astroke to a predetermined focal length. Thereafter, when the second zoomsignal is output during the time from after the half depressingoperation is released until the next shutter release is effected, theauto focal length mode is released. As a result, the operation of thefirst zoom signal output means 102 is inhibited until the next shutterrelease is effected even if the half depressing operation is performed,and the focal length of the photographing lens LE is fixed.

(2) The apparatus according to the invention of FIG. 1B:

When the auto focal length mode is set, the control means 206 operatesthe first zoom signal output means 102 by the first half depressingoperation of the release operation member 101. The auto focal lengthmode is released in response to the drive means 104 effecting zooming bythe first zoom signal. When the second zoom signal is output after saidrelease, the drive means 104 is operated to effect arbitrary zooming.Thereafter, the operation of the first zoom signal output means 102 isinhibited until the auto focal length mode is re-set even if the halfdepressing operation is again performed, and the focal length of thephotographing lens LE is fixed.

(3) The apparatus according to the invention of FIG. 1C:

When the auto focal length mode is set, the control means 306 operatesthe first zoom signal output means 102 by the first half depressingoperation of the release operation member 101 and effects zooming at astroke to a predetermined focal length. Thereafter, when the halfdepressing operation is released without shutter release being effected,the auto focal length mode is released. When the second zoom signal isoutput after said release, the drive means 104 is operated to effectzooming. Thereafter, the operation of the first zoom signal output means102 is inhibited until the auto focal length mode is re-set even if thehalf depressing operation is again performed, and the focal length ofthe photographing lens LE is fixed.

(4) The apparatus according to the invention of FIG. 8:

Describing the present invention with reference to FIG. 8 of theaccompanying drawings an operation controller for a camera according tothe present invention is provided with photometry means 801 outputtingbrightness information regarding the brightness of an object, focallength output means 802 outputting a focal length a photographing lens805 capable of photographing at a plurality of focal lengths shouldassume during the next photographing, exposure value calculating means803 for calculating an exposure value on the basis of at least a fullopen aperture stop value corresponding to the input focal length and thebrightness information, and drive means 804 for driving thephotographing lens 805 until it assumes the output focal length afterthe calculation of the exposure value by said exposure value calculatingmeans 803.

The focal length output means 802 outputs a focal length thephotographing lens 805 should assume during the next photographing. Theexposure value calculating means 803 calculates an exposure value on thebasis of a full open aperture stop value corresponding to said outputfocal length and the brightness information output by the photometrymeans 801. The drive means 804 drives the photographing lens 805 untilit assumes the focal length output by the focal length output means 802after the calculation of the exposure value by the exposure valuecalculating means 803. Thereby, even when flash light emission becomesnecessary, for example, with a change in the focal length, it becomespossible to accomplish flash photography within a very short time afterthe photographing.

The applicant has previously proposed an apparatus. An apparatuspreviously proposed is such that for example, during the above-describedgiven magnification photography, an exposure value is calculated on thebasis of a full open aperture stop value corresponding to the set focallength of the photographing lens and the object brightness and when thisexposure value is a value requiring flash light emission, charging forlight emission is started and thereafter the photographing lens isdriven to said focal length. According to this, charging and lens driveare effected side by side and therefore, if charging has been completedwhen the photographing lens has reached a predetermined focal length,photographing can be immediately effected without waiting for thecharging time.

Again in the apparatus of this type, however, if charging has not beencompleted when the photographing lens has reached the predeterminedfocal length, photographing is effected after the completion of chargingand therefore, which may detract from the quickness of photographing insuch a case. Also, for example, in a camera which is capable ofaccomplishing the above-described given magnification photography andwhich is not provided with an electronic flash device, if adequateexposure is not obtained at a set focal length, it is necessary to giveup photographing or effect photographing with full knowledge that anundesired photograph will result.

Also, in a certain kind of camera a focal length of a photographing lensfor photographing an object at a preset photograph magnification iscalculated on the basis of the object distance detected by a distancemeasuring device or the like with the half depressing operation of arelease button, and the photographing lens is driven to the calculatedfocal length, whereafter photographing is effected with the fulldepressing operation of the release button. Thereby, if a predeterminedphotograph magnification is set, a photograph of the so-called waistshot size in which, for example, the bust of an object (a person) iscontained in the picture plane will be obtained irrespective of theobject distance, simply by the operation of the release button.

Now, the guide number of an electronic flash device is determined by theproduct of the full open F-value of a photographing lens and the objectdistance. Accordingly, in the case of an electronic flash device of apredetermined guide number, an object distance for which flashphotography can be effected (the flash reach distance) can be found fromthis guide number and the full open F-value of the photographing lens.

When, for example, the above-described given magnification photographyis to be effected by the use of such an electronic flash device of apredetermined guide number, if the object distance is great and thephotographing lens is driven to the telephoto side, the full openF-value of the photographing lens becomes great and therefore, theabove-mentioned flash reach distance becomes short. If this flash reachdistance becomes smaller than the object distance, the emitted light ofthe electronic flash device will not sufficiently reach the object andan under-exposed photograph will be taken.

It is still another object of the present invention to secure thequickness of photographing when for example, the above-described givenmagnification photography is effected and to enable photographing to beeffected at adequate exposure.

It is yet another object of the present invention to provide a zoomingcontroller for a camera which prevents under-exposed photographs frombeing taken.

Describing the present invention with reference to FIGS. 15A and 15B ofthe accompanying drawings, the present invention is applied to a focallength controller for use in a camera capable of photographing at aplurality of focal lengths, provided with focal length setting means 151for calculating and setting a focal length which should be assumedduring photographing on the basis of a predetermined condition, anddrive means 152 for driving a photographing lens LE so as to assume theset focal length.

The invention shown in FIG. 15A, is provided with photometry means 153outputting brightness information regarding the brightness of an object,and judgment means 154 for judging whether the light emission of anelectronic flash device is necessary on the basis of at least thebrightness information, and solves the above-noted technical task byconstructing the focal length setting means 151 as follows: the focallength setting means newly calculates and sets a focal length moretoward the wide angle end side than said set focal length so that thelight emission of the electronic flash device becomes unnecessary whenthe judgment means 154 judges that the light emission of the electronicflash device is necessary.

Also, the invention shown in FIG. 15B, is provided with photometry means153 outputting brightness information regarding the brightness of anobject, exposure value calculating means 155 for calculating an exposurevalue on the basis of at least the brightness information, and judgmentmeans 156 for judging whether the calculated exposure value is anadequate value at which adequate exposure is obtained or an inadequatevalue at which adequate exposure is not obtained when photographing iseffected at this exposure value, and solves the above-noted technicaltask by constructing the focal length setting means 151 as follows: thefocal length setting means newly calculates and sets a focal length moretoward the wide angle end side than said set focal length so that anadequate value may be obtained when the judgment means 156 judges thatsaid exposure value is an inadequate value.

(5) The apparatus according to the invention of FIG. 15A:

The focal length setting means 151 newly calculates and sets a focallength more toward the wide angle end side than the focal length set atfirst so that the light emission of the electronic flash device maybecome unnecessary when it is judged by the judgment means 154 that thelight emission of the electronic flash device is necessary. Thereby,photographing can be effected at adequate exposure even if theelectronic flash device is not used and therefore, the quickness ofphotographing can be secured.

(6) The apparatus according to the invention of FIG. 15B:

The focal length setting means 151 newly calculates and sets a focallength more toward the wide angle end side than the focal length set atfirst so that an adequate value may be obtained when the judgment means156 judges that the exposure value calculated by the exposure valuecalculating means 155 is an inadequate value. Thereby, photographing canbe effected at adequate exposure without photographing being given upeven with a camera which is not provided with an electronic flashdevice.

Further describing the present invention with reference to FIG. 19A ofthe accompanying drawings a zooming controller is provided with a zoomlens 191, object distance detecting means 192 for detecting an objectdistance corresponding to the distance to an object, an electronic flashdevice 193 of a predetermined guide number, full open F-value outputmeans 194 outputting a full open F-value varying in conformity with eachfocal length of the zoom lens 191, calculation means 195 for calculatinga flash reach distance on the basis of at least the full open F-value atany focal length of the zoom lens 191 and the guide number of theelectronic flash device 193 during flash photography using theelectronic flash device 193, and lens drive control means 196 forsetting a focal length having such a full open F-value that the flashreach distance is greater than the object distance when the detectedobject distance is greater than the calculated flash reach distance, anddriving the zoom lens 191 so as to assume said focal length, and therebysolve the above-noted technical task.

Describing the present invention with reference to FIG. 19B of theaccompanying drawings, the invention of FIG. 19B is applied to a zoomingcontroller for a camera provided with said zoom lens 191, said objectdistance detecting means 192, and lens drive control means 198 forsetting such a first focal length that the object is photographed at apreset photograph magnification irrespective of the object distancedetected by the object distance detecting means 192, on the basis ofsaid detected object distance, and driving the zoom lens 191 so as toassume said first focal length.

The invention of FIG. 19B is further provided with an electronic flashdevice 193 of a predetermined guide number, full open F-value outputmeans 194 outputting a full open F-value varying in conformity with eachfocal length of the zoom lens 191, and calculation means 197 forcalculating a flash reach distance on the basis of at least the fullopen F-value at the first focal length of the zoom lens 191 and theguide number of the electronic flash device 193 during flash photographyusing the electronic flash device 193, and solves the above-notedtechnical task by constructing the lens drive control means 198 asfollows: the lens drive control means sets a second focal length havingsuch a full open F-value that the calculated flash reach distance isgreater than the object distance detected during the setting of thefirst focal length when said detected object distance is greater thansaid calculated flash reach distance, and drives the zoom lens 191 so asto assume said second focal length.

(7) The apparatus according to the invention of FIG. 19A:

The calculation means 195 calculates a flash reach distance on the basisof at least the full open F-value at any focal length of the zoom lens191 and the guide number of the electronic flash device 193 during flashphotography using the electronic flash device 193. The lens drivecontrol means 196 sets a focal length having such a full open F-valuethat the flash reach distance is greater than the object distance whenthe object distance detected by the object distance detecting means 192is greater than the flash reach distance calculated by the calculationmeans 195, and drives the Zoom lens 191 so as to assume said focallength. Thereby, under-exposed photographs are prevented from beingtaken.

(8) The apparatus according to the invention of FIG. 19B:

The calculation means 197 calculates a flash reach distance on the basisof at least a full open F-value at a first focal length of the zoom lens191 and the guide number of the electronic flash device 193. The lensdrive control means 198 sets a second focal length having such a fullopen F-value that the flash reach distance calculated by saidcalculation means 197 is greater than the object distance detectedduring the setting of the first focal length when said detected objectdistance is greater than said calculated flash reach distance, anddrives the zoom lens 191 so as to assume said second focal length.Thereby, even during given magnification photography, under-exposedphotographs are prevented from being taken.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B and 1C are block diagrams for broadly illustrating certainembodiments of the invention.

FIGS. 2 to 5A show an embodiment of the present invention, in greaterdetail FIG. 2 being a block diagram of a zooming controller for a cameraaccording to the present invention, and FIGS. 3-5A being flow chartsshowing the processing procedure. FIGS. 5B, 5C, 5D show variations ofFIG. 5A.

FIGS. 6 and 7 are flow charts showing modifications of the processingprocedure.

FIG. 8 is a block diagram for broadly illustrating another embodiment ofthe invention.

FIGS. 9, 10, 10A, and 10B show an embodiment of the present invention,FIG. 9 being a block diagram of an operation controller for a cameraaccording to the present invention, and FIGS. 10-10B being a flow chartshowing the processing procedure.

FIGS. 11, 12, 13, 13A, 13B, 13C, 13D, 14, 14A, 14B, 14C, and 14D areflow charts showing modifications of the processing.

FIGS. 15A and 15B are block diagrams for broadly illustrating furtherembodiments of the invention.

FIGS. 16 and 17 show an embodiment of the present invention, in greaterdetail FIG. 16 being a block diagram of a focal length controller for acamera according to the present invention, and FIG. 17 being a flowchart showing the processing procedure.

FIG. 18 is a flow chart of the processing procedure showing anotherembodiment.

FIGS. 19A and 19B are block diagrams for broadly illustrating additionalembodiments of the invention.

FIGS. 20, 21, 21A and 21B show an embodiment of the present invention,in greater detail FIG. 20 being a block diagram of a zooming controllerfor a camera according to the present invention, and FIGS. 21-21B beinga flow chart showing the processing procedure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will hereinafter be describedwith reference to FIGS. 2 to 5.

Referring to FIG. 2, a photometry circuit 2 and a distance measurementcircuit 3 are connected to CPU 1. A light receiving element 4 forreceiving light from an object is connected to the photometry circuit 2,and brightness information (object brightness) regarding the brightnessof the object is calculated on the basis of the detection signal of thelight receiving element 4 and is input to the CPU 1. Connected to thedistance measurement circuit 3 are a projector 6 for projecting a lighttoward the object through projection lens 5 and a light receivingelement 8 for receiving the reflected light from the object through alight receiving lens 7, and distance information (object distance)conforming to the distance to the object is calculated on the basis ofthe detection signal of the light receiving element 8 and is input tothe CPU 1.

Also connected to the CPU 1 are a motor drive circuit 11 for a focusingmotor 9, a zooming motor 21 and a film winding and rewinding motor 10,an exposure control circuit 12 for driving and controlling an exposurecontroller 13, and switches SW1 and SW2 adapted to be closed in responseto the depression of a release button, RB. The switch SW1 is adapted tobe closed by the half depression of the release button, RB and theswitch SW2 is adapted to be closed by the full depression of the releasebutton RB.

The CPU 1 operates the photometry circuit 2 and the distance measurementcircuit 3 by the closing of the switch SW1, and calculates the lensdrive amount for directing a photographing lens, not shown, to theinfocus position, on the basis of the object distance output from thedistance measurement circuit 3 and also calculates the exposure value onthe basis of the object brightness from the photometry circuit 2. Whenthe switch 2 is thereafter closed, the motor 9 is driven through themotor drive circuit 11, and the photographing lens is moved by thecalculated amount of lens movement to thereby accomplish focusing.Thereafter, the exposure controller 13 is driven through the exposurecontrol circuit 12 to thereby effect photographing and the film is woundup by one frame by the motor 10.

Further, switches SW3-SW5 are connected to the CPU 1.

The switch SW3 is a switch adapted to be closed in response to theoperation of a zoom-up button, not shown, and the closed state of theswitch SW3 is maintained as long as the zoom-up button is operated. TheCPU 1 outputs a second zoom signal as long as the switch SW3 is closed,and drives a zoom lens, not shown, by the zooming motor 21 through themotor drive circuit 11 to thereby vary the focal length of thephotographing lens to the telephoto side. That is, so-called zoom-up isaccomplished.

The switch SW4 is a switch operatively associated with a zoom-downbutton, not shown, and the closed state of the switch SW4 is maintainedas long as the zoom-down button is operated. The CPU 1 outputs thesecond zoom signal as long as the switch SW4 is closed, and drives thezoom lens by the motor 21 through the motor drive circuit 11 to therebyvary the focal length of the photographing lens to the wide angle side.That is, so-called zoom-down is accomplished.

The switch SW5 is a momentary type switch adapted to be closed inresponse to the operation of a given magnification photographing button,not shown, and the CPU 1 sets the given magnification photograph mode bythe closing of this switch SW5. During the setting of this givenmagnification photograph mode, so-called given magnificationphotographing in which the main object is photographed always at apredetermined size irrespective of the distance to the object iseffected.

That is, a plurality of focal lengths of the photographing lensconforming to the object distance are stored as magnification tables inthe CPU 1, and in these tables, the ratio of the object distance to thefocal length, i.e., the photograph magnification, is fixed. The CPU 1selects the sets one of an magnification tables by the frequency of theoperation of the given magnification photographing button, i.e., thefrequency of the closing of the switch SW5.

In the camera of the present embodiment, a magnification table A forphotographing the portion of a person to be photographed above his orher neck at a given magnification, a magnification table B forphotographing the bust of the person to be photographed at the givenmagnification and a magnification table C for photographing the wholebody of the person to be photographed at the given magnification arestored. When the switch SW5 is closed once with the given magnificationphotograph mode remaining unset, the above-mentioned given magnificationphotograph mode is set and also the magnification table A is selectedand set, and when the switch SW5 is closed once more, the magnificationtable B is selected and set, and when the switch SW5 is closed onceagain, the magnification table C is selected and set. When the switchSW1 is closed by half depression after the setting of one of themagnification tables, the CPU 1 automatically sets a focal lengthconforming to the object distance obtained by the distance measurementcircuit 3 from the selected magnification table, and outputs a firstzoom signal to the motor drive circuit 11 to drive the photographinglens to this focal length. If the switch SW5 is closed when themagnification table C has been selected, the given magnificationphotograph mode is released.

Also, when after the setting of the given magnification photograph mode,the zoom-up button or the zoom-down button is operated to close theswitch SW3 or SW4, the CPU 1 releases the given magnification photographmode, and outputs the second zoom signal to the motor drive circuit 11to cause the motor 21 to effect zoom-up or zoom-down. Even if the switchSW1 is closed in this state, automatic setting of the focal length anddriving do not take place because the given magnification photographmode is released. When the full depression switch SW2 is thereafterclosed and the above-described photographing operation is performed, theCPU 1 resets the given magnification photograph mode and also re-setsthe previously selected and set magnification table.

In the construction of the above-described embodiment, the switch SW1constitutes a release operation member 101, the CPU 1 constitutes firstzoom signal output means 102 and control means 106, the switches SW3 andSW4 and the CPU 1 together constitute second zoom signal output means103, the switch 105, and the motor drive circuit 11 and the motor 21together constitute drive means 104.

The procedure of the control by the CPU 1 will now be described withreference to the flow charts of FIGS. 3-5A.

FIG. 3 shows the procedure of the magnification table selection. Whenthe switch SW5 is closed, this program is interruptingly started andfirst, at step S1, whether the magnification table A is currently set isjudged. If the judgment is affirmative, at step S6, the magnificationtable B is set and flag FLGB is set, and if the judgment is negative, atstep S2, whether the magnification table B is selected is judged. Ifstep S2 is affirmed, at step S7, the magnification table C is set andflag FLGC is set, and if step S2 is negated, at step S3, whether themagnification table C is set is judged. If step S3 is affirmed, at stepS8, the given magnification photograph mode and flag FLGC are released,and if step S3 is negated, at step S4, the given magnificationphotograph mode is set, and then at step S5, the magnification table Ais selected and flag FLGA is set, whereafter return is made to the usualprocessing. When in the above-described processing, one of flags FLGA,FLGB and FLGC is set, the other two flags are released.

When the switch SW3 or SW4 is closed thereafter, the program of FIG. 4is interruptingly started and first, at step S11, whether the givenmagnification photograph mode is set is judged. If the judgment isnegative, advance is made to step S13, and if the judgment isaffirmative, the given magnification photograph mode is released at stepS12, and then advance is made to step S13. However, the release of theabove-mentioned flags FLGA-C is not effected here. At step S13, whetherthe zoom-up switch SW3 is closed is judged. If the judgment isaffirmative, at step S14, the zoom-up process is effected by the motor21 through the motor drive circuit 11, and return is made to step S13.If step S13 is negated, advance is made to step S15, where whether thezoom-down switch SW4 is closed is judged. If step S15 is affirmed, atstep S16, the zoom-down process is effected by the motor 21 through themotor drive circuit 11, and if step S15 is negated, return is made tothe usual processing.

FIG. 5A shows the procedure of the processing when the switch SW1 isclosed by the half depression of the release button.

When the half depression switch SW1 is closed, this program isinterruptingly started and first, at step S21, the object distanceobtained by the distance measurement circuit 3 and the object brightnessobtained by the photometry circuit 2 are read. Then, at step S22, thelens drive amount for directing the photographing lens to the in-focusposition is calculated on the basis of the object distance and theexposure value is calculated on the basis of the object brightness, andadvance is made to step S23.

At step S23, whether the given magnification photograph mode is set isjudged, and if the judgment is negative, advance is made to step S24. Ifthe judgment is affirmative, at step S41, the set magnification table isreferred to and a focal length conforming to the object distance read atstep S21 is read, and a first zoom signal conforming to that focallength is output and the photographing lens is directed to the selectedfocal length by the motor 21 through the motor drive circuit 11.

Subsequently, at step S24, whether the full depression switch SW2 isclosed is judged, and if the judgment is negative, at step S25, whetherthe switch SW1 is closed is judged. If step S25 is negated, return ismade to the usual processing, and if step S25 is affirmed, return ismade to step S24.

Here, when the switch SW3 or SW4 is closed after step S25 is negated andreturn is made to the usual processing, the above-described program ofFIG. 4 is interruptingly started, and the given magnification photographmode is released and the zoom-up or zoom-down process is effected.

If step S24 is affirmed, advance is made to step S26, where a focusingcommand signal conforming to the lens drive amount calculated at stepS22 is output, and the photographing lens is driven to the in-focusposition by the motor 9 through the motor drive circuit 11.Subsequently, at step S27, the exposure controller 13 for the shutterand the stop is driven through the exposure control circuit 12 to effectphotographing, whereafter at step S28, the film is wound up by one frameby the motor 10 through the motor drive circuit 11, and advance is madeto step S29.

At step S29, whether the given magnification photograph mode is releasedis judged. If the judgment is negative, return is made to the usualprocessing, and if the judgment is affirmative, advance is made to stepS30. At step S30, whether one of flags FLGA, FLGB and FLGC is set isjudged. If step S30 is negated, return is made to the usual processing,and if step S30 is affirmed, at step S31, the given magnificationphotograph mode is again set and advance is made to step S32. At stepS32, whether one of flags FLGA; FLGB and FLGC is set is judged, and ifit is judged that flag FLGA is set, the magnification table A is set atstep S33, and if it is judged that flag FLGB is set, the magnificationtable B is set at step S34, and if it is judged that flag FLGC is set,the magnification table C is set at step S35, and return is made to theusual processing.

According to the above-described procedure, if the half depression ofthe release button is effected when the given magnification photographmode is set, a predetermined focal length is automatically set, and thephotographing lens is driven to this focal length, and if the zoom-upbutton is operated after the half depression is released thereafter, thegiven magnification photograph mode is released and the zoom-up orzoom-down process is effected. Even if the half depression is againeffected thereafter, automatic setting of the focal length and drivingof the photographing lens are not effected. Accordingly, if thecomposition by the focal length set by the camera side is notsatisfactory when the half depression is effected after the givenmagnification photographing button is operated, the half depression maybe released and then the zoom-up-down button may be operated to finelyadjust the focal length, and thereafter the release operation may beeffected, whereby photographing can be effected at a desired focallength. Also, the given magnification photograph mode released by theoperation of the zoom-up-down button is reset in response to thecompletion of photographing and the previously set magnification tableis likewise reset and therefore, it is not necessary to manually re-setthe given magnification photograph mode released with the manualoperation of the zoom-up or zoom-down switch each time photographing isterminated and thus, operability is improved.

In FIG. 5A, there is shown an example in which the photographing lens isautomatically driven to the set focal length by the half depressingoperation, whereafter the half depression is released and then manualzooming is effected, whereby the given magnification photograph mode isreleased and thereafter, the given magnification photograph mode isagain set when photographing is effected, but the steps S29-S35 of FIG.5A may be deleted so that the resetting of the given magnificationphotograph mode may not be effected.

In the following there will be explained FIGS. 5B, 5C and 5D showingvariations of FIG. 5A.

FIG. 5B contains a new step S21A between the steps S41 and S24 shown inFIG. 5A. Step S21A is the same function as the step S21. In FIG. 5B,after the zooming in the step S41, the step S21A activates the distancemeasurement circuit 3 and the photometry circuit 2 again, therebyobtaining information on the object distance and the object brightness.The focusing operation in the step S26 is conducted on the informationon the object distance, and the exposure operation in the step S27 isconducted on the information on the object brightness.

Consequently, even if the object distance and the object brightness varyduring the zooming in the step S41, the focusing and the exposureoperation can follow such variations. The foregoing information isretained as long as the step S25 identifies the on-state of the halfdepression switch Sw1. If the step S25 identifies the off-state thereof,the process of FIG. 5B is terminated. If the half depression switch Sw1is turned on again, the distance measurement and the photometry areconducted again in the step S21 in FIG. 5B, and the information on theobject distance and the object brightness obtained in the step S21A arerenewed.

FIG. 5C contains a step S21B inserted between the YES line of the stepS24 and the step S26 in FIG. 5A. Step S21B is of the same function asthat of the step S21. In the sequence shown in FIG. 5C, after the stepS24 identifies the on-state of the full depression switch Sw2, the stepS21B activates the distance measurement circuit 3 and the photometrycircuit 2 again, thereby obtaining information on the object distanceand the object brightness. The focusing in the step S26 is conducted onthe information on the object distance, and the exposure operation inthe step S27 is conducted on the information on the object brightness.

Consequently, even if the object distance and the object brightness varyduring the zooming of the step S41, or during the repeated execution ofthe steps S24 and S25 due to the on-state of the half depression switchSw1 and the off-state of the full depression switch Sw2, the focusingand the exposure operation can follow such variations.

FIG. 5D shows a variation of the step S41 in FIG. 5A.

If the discrimination of the step S23 in FIG. 5A turns out affirmative,indicating the setting of the given magnification photograph mode, astep S41A starts zooming. Thereafter the step 41B discriminates whetherzooming has been completed, namely whether the photographing lens hasreached the selected focal length. If the discrimination of the step 41Bturns out negative, a step S41C discriminates whether either the zoom-upswitch Sw3 or the zoom-down switch Sw4 has been turned on. If negative,the sequence returns to the step S41B. The steps S41B and S41C arerepeated until affirmative discrimination is obtained in either step.

If the step S41C provides an affirmative result by the closing of thezoom-up switch Sw3 or the zoom-down switch Sw4, a step S41D terminatesthe zooming. Thereafter the routine of FIG. 5C is terminated, and thesequence returns to the routine in FIG. 4, starting from the step S11.Thus there are conducted the releasing of the given magnificationphotograph mode and the zooming in response to the manipulation of theswitch Sw3 or Sw4.

If the step S41B provides an affirmative result by the arrival of thephotographing lens at the selected focal length, a step S41E terminatesthe zooming. Thereafter the sequence starting from the step S24 in FIG.5A is executed.

As explained above, this variation provides superior operability, since,if the zoom-up switch Sw3 or the zoom-down switch Sw4 is turned onduring the zooming of the step S41, in response the releasing of thegiven magnification photograph mode and the zooming according to themanipulation of the switch Sw3 or Sw4 are executed.

In the foregoing, there is shown an example in which the givenmagnification photograph mode is released by the operation of thezoom-up button and the zoom-down button. An example in which the givenmagnification photograph mode is released immediately after zooming orafter the release of the half depression will now be described withreference to FIGS. 6 and 7. In FIGS. 6 and 7, steps similar to those ofFIG. 5 are given similar reference characters.

In FIG. 6, if at step S23, the setting of the given magnificationphotograph mode is judged, advance is made to step S41, where the setmagnification table is referred to set a focal length corresponding tothe object distance and the photographing lens is driven to this focallength and zooming is effected, whereafter at step S61, the givenmagnification photograph mode is released. Thus, again, as describedabove, if the half depression is released and the focal length is finelyadjusted, the focal length will not be changed by the half depressionthereafter and photographing can be accomplished at a compositionintended by the photographer.

Further, in FIG. 7, when after the zooming at step S41, the closing ofthe full depression switch SW2 is negated at step S24 and the closing ofthe half depression switch SW1 is judged at step S25, the givenmagnification photograph mode is released at step S71 and return is madeto the usual processing. According to this, there is obtained the effectthat photographing can be accomplished at a composition intended by thephotographer as described above, and unlike the embodiment of FIG. 6 butas in the embodiment of FIG. 5, the setting of the given magnificationphotograph mode is continued even after the photographing of step S26and subsequent steps is effected without the half depression beingreleased, and this is convenient when given magnification photographingis to be continuously effected. Also, in the embodiment of FIG. 5, thegiven magnification photograph mode is maintained even if the halfdepression switch SW1 is released after the termination ofphotographing, and it is necessary to operate the mode switch SW5 torelease the given magnification photograph mode, whereas in theembodiment of FIG. 7, the given magnification photograph mode isreleased when the half depression switch SW1 is released and therefore,mode change can be done from the given magnification photograph mode tothe usual photograph mode without the necessity of any specialoperation.

In the embodiment of FIGS. 6 and 7, the resetting of the givenmagnification photograph mode is not effected after photographing andtherefore, it is not necessary to effect the setting of the flags at thesteps S5-S7 of FIG. 3, and the given magnification photograph mode isnot released by the closing of the switches SW3 and SW4 and therefore,the steps S11 and S12 of FIG. 4 are unnecessary.

Further, in the foregoing, a case where the setting of the givenmagnification is effected, whereas the present invention is notrestricted thereto, but is also applicable to a camera in which, forexample, a desired focal length is input in advance by a manualoperation and the photographing lens is driven to the input focal lengthby the half depression of the release button.

According to the invention of FIG. 1A, during the set auto focal lengthmode, the photographing lens is automatically driven to the focal lengthset on the camera by the half depressing operation, and when themanually operated zooming operation member is operated from after thehalf depressing operation is thereafter released until the next shutterrelease, said mode is released, and even if the half depressingoperation is performed, zooming to the focal length set on the camera isnot effected until the next shutter release is effected and therefore,when it is desired to change the focal length automatically set afterthe half depression, the half depression is once released and then thefocal length of the photographing lens is adjusted by the operation ofthe manually operated zooming operation member, whereafter the fulldepressing operation is performed, whereby photographing can beaccomplished at a desired focal length and thus, the operability of thecamera is improved.

Also, according to an embodiment of the invention during the set autofocal length mode, the photographing lens is automatically driven to thefocal length set on the camera by the half depressing operation andafter the driving, this mode is released and thereafter, zooming to thefocal length set on the camera is not effected even if the halfdepressing operation is performed and therefore, as described above,when it is desired to change the automatically set focal length, thehalf depression is once released and then the drive means is driven bymanual operation to thereby adjust the focal length of the photographinglens, whereafter the full depressing operation is performed, wherebyphotographing can be accomplished at a desired focal length and thus,the operability of the camera is improved.

Further, according to the invention of FIG. 1B, during the set autofocal length mode, the photographing lens is automatically driven to thefocal length set on the camera by the half depressing operation, andwhen the half depressing operation is released without shutter releasebeing effected, this mode is released and thereafter, zooming to thefocal length set on the camera is not effected even if the halfdepressing operation is performed, and therefore an effect similar tothat described above is obtained and the auto focal length mode iscontinued as long as the half depression is not released, and this isconvenient when for example, given magnification photographing iseffected continuously.

Another embodiment of the present invention will now be described withreference to FIGS. 9-10B.

FIG. 9 is a block diagram of the operation controller of the cameraaccording to the present invention. A distance measurement circuit 92, aphotometry circuit 93 and a magnification setter 94 are connected to CPU91. The distance measurement circuit 92 outputs measured distance dataconforming to the distance to an object, and the photometry circuit 93outputs brightness information regarding the brightness of the object.The magnification setter 94 outputs a photographing magnification presetand input, for example, by a button operation.

Also connected to the CPU 91 are the flash circuit 95 of an electronicflash device, a motor drive circuit 96, an exposure control circuit 97and a zoom encoder 90. The flash circuit 95 charges a light emittingcapacitor, not shown, and causes the light emitting tube thereof to emitlight by the charge. The motor drive circuit 96 controls a motor 98 anddrives a zoom lens 99 to a predetermined focal length, and the positionof this zoom lens 99 is detected by the zoom encoder 90. The exposurecontrol circuit 97 drives exposure control members such as a shutter anda stop, not shown.

Further connected to the CPU 91 are switches SW1 and SW2 adapted to beclosed in response to the operation of a release button, not shown. Theswitch SW1 is closed by the half depression of the release button, andthe switch SW2 is closed by the full depression of the release button.When these switches SW1 and SW2 are closed, the CPU 91 controls theabove-mentioned circuits and effects a series of photographing processesas will be described later.

In the construction of the above-described embodiment, the photometrycircuit 93 constitutes photometry means 801, the CPU 91 and the distancemeasurement circuit 92 together constitute focal length output means802, the CPU 91 constitutes exposure calculation means 803, the motordrive circuit 96 and the motor 98 together constitute drive means 804,and the zoom lens 99 constitutes a photographing lens 805.

The procedure of the operation of the camera by the CPU 91 will now bedescribed with reference to the flow chart of FIGS. 10-10B.

This program is started when the half depression switch SW1 is closed,and first, at step S101, measured distance data x representing thedistance to the object obtained by the distance measurement circuit 92is read. Subsequently, at step S102, a preset photograph magnification Mis read from the magnification setter 94, and advance is made to stepS103. At step S103, on the basis of the read measured distance data xand the photograph magnification M, the focal length f which the zoomlens 99 should assume during the next photographing is calculated byf=M×x. Subsequently, at step S104, a full open aperture stop value Fcorresponding to the focal length f calculated at step S103 is foundfrom among a plurality of full open aperture stop values preset andstored in conformity with the focal lengths of the zoom lens 99. At stepS105, the brightness information b regarding the brightness of theobject obtained by the photometry circuit 93 is read, and advance ismade to step S106. At step S106, an exposure value is calculated on thebasis of the brightness information b, the full open aperture stop valueF found at step S104, and film speed information or the like. On thebasis of this calculated exposure value, the aperture value, the shutterspeed, etc. are determined and the presence or absence of the necessityof flash light emission is also determined.

At step S107, whether flash light emission is needed is judged, and ifthe judgment is affirmative, advance is made to step S108. At step S108,whether the charging of the light emitting capacitor is completed isjudged, and if the judgment is negative, an alarm to the effect that thecharging is not completed is output at step S109, and advance is made tostep S110. At step S110, whether the half depression switch SW1 isclosed is judged, and if this switch is opened, this processingprocedure is advanced to END to thereby terminate the photographingoperation, and if the switch SW1 is closed, at step S110, the driving ofthe zoom lens 99 is started by the motor 98 through the motor drivecircuit 96 so that the zoom lens 99 assumes the focal length fcalculated at step S103, and at step S112, the charging of the lightemitting capacitor is started.

Advance is then made to step S113, where whether the zoom lens 99 hasassumed the above-mentioned focal length f on the basis of the signal ofthe zoom encoder 90 is judged. If the judgment is affirmative, advanceis made to step S114, where the driving of the zoom lens 99 is stopped,and at step S115, whether the charging of the light emitting capacitorhas been completed is judged. If the judgment is affirmative, thecharging is stopped at step S116, and the above-mentioned alarm isreleased at step S117, whereafter advance is made to step S118. If stepS115 is negated, the program stays at step S115 until step S115 isaffirmed, whereafter advance is made to step S118 via steps S116 andS117.

If step S113 is negated, advance is made to step S120, where whether thecharging has been completed is judged. If the judgment is negative,return is made to step S113, and if the judgment is affirmative, advanceis made to step S121, where the charging is stopped, and at step S122,the alarm is released. Subsequently, at step S123, whether the zoom lens99 has assumed the aforementioned focal length f is judged. If thejudgment is affirmative, the driving of the zoom lens 99 is stopped atstep S124, whereafter advance is made to step S118. If the judgment isnegative, the program stays at step S123 until the judgment becomesaffirmative, whereafter advance is made from step S124 to step S118.

At step S118, whether the full depression switch SW2 is closed isjudged. If the judgment is affirmative, advance is made to step S119,where the stop and the shutter are driven on the basis of the exposurevalue calculated at step S106 and photographing is effected. If stepS118 is negated, at step S171, whether the half depression switch SW1 isOFF is judged, and if the judgment is affirmative, advance is made toEND, and if the judgment is negative, return is made to step S118.

Also, if step S107 is negated or step S108 is affirmed, advance is madeto step S125, where the driving of the zoom lens 99 is started. Then, atstep S126, whether the zoom lens 99 has assumed the predetermined focallength f is judged, and if the judgment is affirmative, at step S127,the zoom lens 99 is stopped, and advance is made to step S118, wherephotographing is effected. If the judgment is negative, the programstays at step S126 until the judgment becomes affirmative.

According to the above-described procedure, exposure calculation iseffected before the zoom lens 99 is driven to the predetermined focallength f, and the presence or absence of the necessity of flash lightemission is judged on the basis of the result of the calculation, and ifthe flash light emission is judged as necessary and the charging is notcompleted, an alarm of uncompleted charging is produced. If the chargingis completed while the zoom lens 99 is driven to the predetermined focallength f, photographing accompanied by flash light emission immediatelybecomes possible at a point of time whereat the driving of the zoom lens99 is terminated. On the other hand, it is possible that the charging isnot yet completed at the point of time whereat the driving of the zoomlens 99 is terminated, but the user is informed of the fact of theuncompleted charging in advance by an alarm and therefore, the user canbe prepared for it and will no longer feel displeased by photographingbeing inhibited after the driving of the lens.

Modifications

(1) In FIGS. 10-10B, the design is such that if the half depressionswitch SW1 is opened after the alarm of uncompleted charging, all theoperation is terminated by step S110, but step S110 may be deleted andthe design may be such that even if the half depression switch SW1 isopened before the driving of the zoom lens 99, the driving of the zoomlens 99 and the charging are effected.

FIGS. 11 and 12 show modifications of the processing when the halfdepression switch SW1 is judged as being OFF at step S110.

(2) In FIG. 11, if step S108 is negated, an alarm of uncompletedcharging is not output, but advance is made to step S110. At step S110,whether the half depression switch SW1 is closed is judged, and if thejudgment is negative, there is a predetermined wait time at step S131,whereafter advance is made to step S132, where an alarm of uncompletedcharging is output. Subsequently, at step S133, the charging is started,whereafter at step S134, whether the charging has been completed isjudged. If the judgment is affirmative, advance is made to step S136,and if the judgment is negative, at step S135, whether the halfdepression switch SW1 is closed is judged. If step S135 is affirmed,return is made to step S132, and if step S135 is negated, advance ismade to step S136. At step S136, the above-mentioned alarm is stopped,whereafter at step S137, the charging is stopped and the processing isterminated.

According to the above-described processing, when the half depressionswitch SW1 is again closed within a predetermined time after the openingof the half depression switch SW1 at step S110, the alarm of uncompletedcharging and the charging are continued. Accordingly, confirmation ofthe charged state can be readily accomplished.

(3) Also, in FIG. 12, if step S110 is negated, advance is made to stepS141, where the charging is started, and then at step S142, an alarm ofuncompleted charging is output, whereafter at step S143, whether thecharging has been completed is judged. If the judgment is negative,return is made to step S141, and if the judgment is affirmative, thecharging is stopped at step S144, and at step S145, the alarm isreleased and the processing is terminated.

According to the above-described processing, the charging is effected asa temporary measure even if the half depression switch SW1 is opened,and this is effective for the use of a lithium battery or the like whichcan be rapidly charged.

Further, FIGS. 13-14D show modifications of the timing of the releaseoperation. In these figures, steps similar to those in FIGS. 10-10B aregiven similar reference characters.

(4) In FIGS. 13-13B, after the start of the lens driving at step S111,whether the full depression switch SW2 is closed is judged at step S151.If the judgment is negative, the processing of step S112 and subsequentsteps (described in connection with FIGS. 10-10B) is effected, and ifthe judgment is affirmative, the driving of the zoom lens 99 is stoppedat step S152 even if the focal length f is not reached, whereafteradvance is made to step S119, where photographing is effected. If stepS107 is negated or step S108 is affirmed, the driving of the zoom lens99 is started at step S125, whereafter advance is made to step S153. Atstep S153, whether the full depression switch SW2 is closed as describedabove is judged, and if the judgment is negative, the processing of stepS126 and subsequent steps is effected, and if the judgment isaffirmative, the driving of the zoom lens 99 is stopped at step S152,whereafter the photographing operation is performed at step S119.

According to the above-described processing, if the full depressionswitch SW2 is closed after the driving of the zoom lens 99 toward thepredetermined focal length f is started, photographing is effected inspite of the zoom lens 99 being not driven to a predetermined focusposition and therefore, quickness of photographing can be secured. FIGS.13C and 13D show a variation in which the NO line of the step S120 inFIG. 13B leads to the step S151, and the NO line of the step S126 leadsto the step 153. Consequently, the discrimination of the step S151 orS153 is repeatedly executed in a period from the start of zooming in thestep S111 or S125 in FIG. 13A to the identification of completed zoomingin the step S113 or S126, so that the sequence can proceed to thetermination of zooming (step S152) and the photographing operation (stepS119) in response to the closing of the full depression switch SW2 atany time during the zooming.

(5) Also, in FIGS. 14-14B, at step S111, the driving of the zoom lens 99is started, whereafter at step S161, whether the full depression switchSW2 is closed is judged. If the judgment is negative, the processing ofstep S112 and subsequent steps is effected, and if the judgment isaffirmative, the switch-on flag FLG is turned on at step S162, andadvance is made to step S112. If step S107 is negated or step S108 isaffirmed, the driving of the zoom lens 99 is likewise started at stepS125, whereafter at step S163, whether the full depression switch SW2 isclosed is judged, and if the judgment is negative, advance is made tostep S126, and if the judgment is affirmative, the switch-on flag FLG isturned on at step S164, and advance is made to step S126. Further, atstep S165, whether the switch-on flag FLG is ON is judged before the ONor OFF of the full depression switch SW2 is judged at step S118, and ifthe judgment is negative, advance is made to step S118, and if thejudgment is affirmative, advance is made to step S119, where thephotographing operation is performed.

According to the above-described procedure, if the full depressionswitch SW2 is closed after the driving of the zoom lens 99 is startedand before the zoom lens 99 assumes the predetermined focal length f,this closed state is maintained until after the driving of the zoom lensis completed. FIGS. 14C and 14D show a variation in which the NO line ofthe step S120 in FIG. 14B leads to the step S161 and the NO line of thestep S126 in FIG. 14B leads to the step S163. Consequently thediscrimination of the step S161 or S163 is repeatedly executed in aperiod from the start of zooming in the step S111 or S125 in FIG. 14A tothe identification of completed zooming in the step S114 or S126, sothat the flag-on operation of the step S162 or S164 can be executedimmediately in response to the closing of the full depression switch Sw2at any time during the zooming. Accordingly, even if the user fullydepresses the release button before the zoom lens 99 assumes thepredetermined focal length f, and thereafter releases the finger fromthe release button, photographing will be effected after the driving ofthe zoom lens 99 is completed.

In the foregoing, there has been shown an example in which the focallength f of the zoom lens 99 is calculated on the basis of the measureddistance data x output from the distance measurement circuit 92 and thepresent photograph magnification M and the full open aperture stop valueF corresponding to said focal length f is used in the calculation of theexposure value, but for example, during so-called zoom continuousphotography in which several focal lengths are set and input in advanceand the zoom lens 99 is driven to the input focal length f andphotographing is effected each time, a full open aperture stop valuecorresponding to said input and set focal length f may be found and maybe used in the calculation of the exposure value.

Also, in the foregoing, a zoom lens has been described, but the presentinvention is applicable to any of photographing lenses which canaccomplish photographing at a plurality of focal lengths.

According to the present invention, the exposure value is calculated onthe basis of the full open aperture stop value corresponding to thefocal length the photographing lens capable of photographing at aplurality of focal lengths should assume during the next photographingand the brightness information output from the photometry means, andafter the calculation of the exposure value, the photographing lens isdriven until it assumes said focal length and therefore, for example,the presence or absence of the necessity of flash light emission can beknown before the photographing lens is driven and thus, the operabilityof the camera is improved.

Still another embodiment of the present invention will now be describedwith reference to FIGS. 16 and 17.

FIG. 16 is a block diagram of the focal length controller of a cameraaccording to the present invention. A distance measurement circuit 162and a photometry circuit 163 are connected to CPU 161. The distancemeasurement circuit 162 detects measured distance data according to thedistance to an object and inputs it to the CPU 161, and the photometrycircuit 163 detects brightness information regarding the brightness ofthe object and inputs it to the CPU 161.

Also connected to the CPU 161 are the flash circuit 165 of an electronicflash device, a motor drive circuit 166, an exposure control circuit 167and a zoom encoder 160. The flash circuit 165 charges a light emittingcapacitor, not shown, and causes the light emitting tube thereof to emitlight by this charge. The motor drive circuit 166 controls a motor 168and drives a photographing lens 169 to a predetermined focal length, andthe position of this photographing lens 169 is detected by the zoomencoder 160. The exposure control circuit 167, as will be describedlater, drives an exposure control device such as a shutter and a stop,not shown, on the basis of the exposure value calculated in the CPU 161and accomplishes photographing.

Further connected to the CPU 161 are switches SW1 and SW2 adapted to beclosed in response to the operation of a release button, not shown. Theswitch SW1 is closed by the half depression of the release button, andthe switch SW2 is closed by the full depression of the release button.When these switches SW1 and SW2 are closed, the CPU 161 controls theabove-mentioned circuits and effects a series of photographingprocesses.

A magnification setter 164 is further connected to the CPU 161 andinputs to the CPU 161 a photograph magnification conforming to theobject size input, for example, by a button operation. That is, thecamera of the present embodiment is capable of given magnificationphotographing in which the object is photographed at a predeterminedobject size irrespective of the object distance, and a mode in whichthis given magnification photographing is accomplished by the operationof a given magnification setting button (the given magnificationphotograph mode) is set in the CPU 161. As regards the object size, forexample, the so-called waist shot size in which the bust of the object(a person) is contained in the picture plane and the full shot size inwhich the whole body of the object is contained in the picture plane canbe designated, and one of these object sizes is designated by thefrequency of the operation of the above-mentioned given magnificationsetting button. The magnification setter 164 sets a photographmagnification corresponding to the designated object size and inputs itto the CPU 161.

The CPU 161, during the setting of the given magnification photographmode, calculates the focal length of the photographing lens (zoom lens)169 on the basis of the input photograph magnification and the objectdistance from the distance measurement circuit 162, and also calculatesthe exposure value from the full open aperture stop value of thephotographing lens 169 corresponding to said focal length, thebrightness information detected by the above-mentioned photometrycircuit 163 and the film speed information. Whether the light emission(flash light emission) of the electronic flash device is necessary isjudged on the basis of this exposure value, and if it is necessary, thefocal length is changed as will be described later.

In the construction of the above-described embodiment, the photometrycircuit 163 constitutes photometry means 153, the CPU 161 and thedistance measurement circuit 162 together constitute focal lengthsetting means 151, the CPU 161 constitutes judgment means 154, and themotor drive circuit 166 and the motor 168 together constitute drivemeans 152.

The control procedure of the camera by the CPU 161 will now be describedwith reference to the flow chart of FIG. 17.

When the given magnification photograph mode and a desired object sizeare set by the operation of a given magnification photograph button andthereafter the switch SW1 is closed by the half depressing operation ofa release button, the program of FIG. 17 is started and first, at stepS201, measured distance data x representing the distance to the objectobtained by the distance measurement circuit 162 is read. Subsequently,at step S202, a photograph magnification M corresponding to the objectsize set by the magnification setter 164 is read, and advance is made tostep S203. At step S203, on the basis of the read measured distance datax and the photograph magnification M, the focal length f thephotographing lens 169 should assume during the next photographing iscalculated by f=M×x. Subsequently, at step S204, a full open aperturestop value F corresponding to the focal length f calculated at step S203is selected from among a plurality of full open aperture stop values setand stored in advance in conformity with the focal lengths of thephotographing lens 169. At step S205, brightness information b regardingthe brightness of the object obtained by the photometry circuit 163 isread, and advance is made to step S206. At step S206, the exposure valueis calculated on the basis of this brightness information b, the fullopen, aperture stop value F obtained at step S204, and further the filmspeed information, etc. The aperture value, the shutter speed, etc. aredetermined on the basis of this calculated exposure value.

At step S207, whether flash light emission is needed is judged. That is,when the shutter speed based on the calculated exposure value is higherthan the camera-shake limit value of a preset shutter speed, it isjudged that flash light emission is not needed, and when said shutterspeed is equal to or lower than the camera-shake limit value, it isjudged that flash light emission is needed. If step S207 is negated, atstep S217, the photographing lens 169 starts to be driven toward thefocal length f calculated at step S203, by the motor 168 through themotor drive circuit 166. Then, at step S218, whether the photographinglens 169 has reached this focal length f is judged from the output ofthe zoom encoder 160. If step S218 is negated, the program stays at stepS218 until step S218 is affirmed, and if step S218 is affirmed, thephotographing lens 169 is stopped at step S219, and advance is made tostep S215.

If step S207 is affirmed, advance is made to step S208. At step S208,whether the charging of the light emitting capacitor is completed isjudged, and if the judgement is negative, an alarm of uncompletedcharging is output and advance is made to step S209, where a focallength f' removing the necessity of flash light emission is newlycalculated and set. That is, as the focal length of the photographinglens 169 becomes greater, the full open aperture stop value thereofbecomes greater and therefore, the shutter speed becomes correspondinglylower and the necessity of flash light emission increases. Accordingly,here, a focal length having such a full open aperture stop value thatthe shutter speed becomes higher than the camera-shake limit value,i.e., a focal length more toward the wide angle end side than the focallength set at first, is set. At step S216 which will be described later,photographing is effected on the basis of the then set shutter speed andthe aperture value corresponding thereto.

For example, when the photographing lens 169 is at the telephoto endposition, flash light emission becomes necessary for an exposure value(Ev value) of 11.5 Ev or less, and when the photographing lens 169 is atthe wide angle position, flash light emission becomes necessary for anexposure value of 9.5 Ev or less. Assuming that the object brightness isb=5 (Bv) and the film speed is ISO100, the Ev value at this time is Ev10and therefore, at the telephoto end position, flash light emissionbecomes necessary, but at the wide angle end position, flash lightemission becomes unnecessary.

Then, at step S210, whether the newly set focal length f' is smallerthan the focal length f₀ at the wide angle end of the photographing lens169 is judged. If step S210 is affirmed, charging is started at stepS211, whereafter advance is made to step S217, and at steps S217-S219,the photographing lens 169 is driven so that the focal length may assumethe original value f calculated at step S203.

On the other hand, if step S210 is negated, at step S212, thephotographing lens 169 starts to be driven toward the focal length f'calculated at step 209 by the motor 168 through the motor drive circuit166. Then, at step S213, whether the photographing lens 169 has reachedthe focal length f' is judged from the output of the zoom encoder 160.If step S213 is negated, the program stays at step S213 until step S213is affirmed, and if step S213 is affirmed, the photographing lens 169 isstopped at step S214, and advance is made to step S215.

At step S215, whether the full depression switch SW2 is closed isjudged, and if the judgment is negative, advance is made to step S223.At step S223, whether the half depression switch SW1 is closed isjudged, and if this switch is opened, this processing procedure isadvanced to END to terminate the operation, and if the switch SW1 isclosed, return is made to step S215. If step S215 is affirmed, advanceis made to step S216, where photographing is effected. That is, thephotographing lens 169 is first driven to a predetermined focusingposition by a focusing motor, not shown, on the basis of the measureddistance data x obtained at step S201, and then the stop and the shutterare driven to effect exposure on the basis of the exposure value set atstep S206 or step S209, whereafter the processing is terminated. Also,during photographing, flash light emission is effected as required.

According to the above-described procedure, when it is judged at stepS207 that the exposure value calculated at step S205 is a value whichrequires flash light emission and uncompleted charging is judged at stepS208, the focal length is changed at step S209 so that flash lightemission becomes unnecessary. Then, at steps S212-S214, thephotographing lens is driven to the changed focal length, and at stepS216, photographing is effected. However, if the changed focal length f'is smaller than the focal length f₀ at the wide angle end, flash lightemission is necessary at any settable focal length and therefore, atstep S211, the charging is started to effect flash photography, and thephotographing lens 169 is driven so as to assume the focal length fbefore changed.

Another Embodiment

In the foregoing, a camera provided with an electronic flash device hasbeen described, and another embodiment using a camera which is notprovided with an electronic flash device will now be described withreference to FIG. 18. In FIG. 18, steps similar to those in FIG. 17 aregiven similar reference characters, and only the differences betweenFIGS. 17 and 18 will hereinafter be described.

In FIG. 18, when the exposure value is calculated at step S206 asdescribed above, advance is made to step S231, where whether adequateexposure is obtained when photographing is effected at this exposurevalue, that is, whether this exposure value is an adequate value, isjudged. This is judged, for example, by whether the shutter speed basedon the calculated exposure value is higher than the camera-shake limitvalue of the preset shutter speed. If step S231 is affirmed, advance ismade to step S217, and if step S231 is negated, advance is made to stepS232.

At step S232, a focal length f' for which adequate exposure can beobtained is newly set. That is, as described above, as the focal lengthof the photographing lens 169 becomes greater, the full open aperturestop value thereof becomes greater and therefore, the shutter speedbecomes correspondingly lower. Accordingly, in such case, a focal lengthhaving such a full open aperture stop value that the shutter speedbecomes higher than the camera-shake limit value, i.e., a focal lengthmore toward the wide angle end side than the focal length set at first,is set.

Further, if step S210 is affirmed, adequate exposure is not obtained atany focal length and therefore, photographing is inhibited and theprocessing is terminated.

According to the above-described procedure, when it is judged that thecalculated exposure value is an inadequate value, the focal length ischanged so that adequate exposure may be obtained, and the photographinglens is driven to the changed focal length.

The judgment as to whether adequate exposure is obtained may be donedepending on whether the calculated exposure value is within the rangeof the exposure value controllable in the camera. For example, when theaperture value based on this exposure value is greater than the fullopen aperture stop value of the focal length at that point of time, itmay be judged that adequate exposure is not obtained.

Also, in the embodiments described above, given magnificationphotographing has been mentioned as calculating and setting the focallength which should be assumed during photographing on the basis ofpredetermined conditions, but this is not restrictive. The presentinvention is also applicable when effecting, for example, so-called zoomcontinuous photography in which several focal lengths are set and inputin advance and the photographing lens 169 is driven to the input focallength f and photographing is effected each time, or so-called step zoomin which the photographing lens is driven to the focal length f input asdescribed above each time the release button is half-depressed.

Also, in the foregoing, the present invention has been described withrespect to a zoom lens, but the present invention is also applicable toany photographing lens capable of photographing at a plurality of focallengths, such as a two-focus or three-focus lens.

According to the invention of FIG. 15A, when it is found that the lightemission of the electronic flash device is necessary in a case wherephotographing is effected at a focal length calculated and set on thebasis of predetermined photographing conditions, a focal length moretoward the wide angle end side than said set focal length is newlycalculated and set so that the light emission of the electronic flashdevice may become unnecessary and therefore, when effecting, forexample, given magnification photographing, the object size set at firstis changed, but photographing can be effected at adequate exposurewithout waiting for the charging time for light emission, and quicknessof photographing can be secured.

According to the invention of FIG. 15B, when it is judged that theexposure value is an inadequate value (a value at which adequateexposure is not obtained) in a case where, as described above,photographing is effected at the focal length calculated and set on thebasis of predetermined photographing conditions, a focal length moretoward the wide angle end side than said set focal length is newlycalculated and set so that an adequate value (a value at which adequateexposure is obtained) may be obtained and therefore, when effecting, forexample, given magnification photographing, the object size set at firstis changed, but photographing can be effected at adequate exposurewithout giving up the photographing.

Yet still another embodiment of the present invention will now bedescribed with reference to FIGS. 20-21B.

Referring to FIG. 20 which shows the entire construction, a distancemeasurement circuit 202 and a photometry circuit 203 are connected toCPU 201. The distance measurement circuit 202 detects distanceinformation (object distance) according to the distance to an object andoutputs it to the CPU 201, and the photometry circuit 203 detectsbrightness information regarding the brightness of the object andoutputs it to the CPU 201.

Also connected to the CPU 201 are a motor drive circuit 204, anindication circuit 205, the flash control circuit 231 of an electronicflash device 230, an exposure control circuit 207 and switches SW1 andSW2, and connected to the motor drive circuit 204 are a zooming motor211, a focusing motor 212 and a film winding motor 213. The motor drivecircuit 204 drives a photographing lens (zoom lens) LE, to apredetermined focal length by the motor 211 in response to a zoomingsignal from the CPU 201. The photographing lens LE in the presentembodiment has its focal length variable from 35 mm (Wide end) to 80 mm(Tele end). The motor drive circuit 204 also drives the photographinglens LE to a predetermined focusing position by the motor 212 inresponse to a focusing signal from the CPU 201, and also winds up thefilm by one frame by the motor 213 in response to a wind-up signal.

LED's 221 and 222 for indication in the viewfinder are connected to theindication circuit 205, and as will be described later, the LED's 221and 222 are turned on in response to an indication signal from the CPU201, thereby effecting various indications. The exposure control circuit207 drives an exposure control device such as a stop and a shutter by acommand from the CPU 201 to thereby effect photographing.

The flash control circuit 231 starts the charging of a light emittingmain capacitor, not shown, in response to a charging start signal fromthe CPU 201 and also causes a light emitting tube 232 to emit light inresponse to a light emission start signal. The CPU 201 judges whetherthe use of the electronic flash device 230 is necessary, on the basis ofthe brightness information or the like from the photometry circuit 203,and when it judges that the use of the electronic flash device 230 isnecessary, it outputs a charging start signal and also outputs a lightemission start signal as photographing progresses.

The switches SW1 and SW2 are switches adapted to be closed in responseto the operation of a release button, not shown, and the switch SW1 isclosed by the half depression of the release button, and the switch SW2is closed by the full depression of the release button. The CPU 201operates the distance measurement circuit 202 and the photometry circuit203 with the closing of the switch SW1, and effects focusing andphotographing through the motor drive circuit 204 and the exposurecontrol circuit 207 with the closing of the switch SW2.

Further connected to the CPU 201 is a switch SW3 adapted to be closed inresponse to the operation of an auto framing mode setting button, notshown, and the CPU 201 sets the auto framing mode with the closing ofthis switch SW3. The auto framing mode is a mode in which is effectedauto framing photography (given magnification photography) in which theobject is photographed always at a predetermined photographmagnification irrespective of the object distance detected by thedistance measurement circuit 202, and this photograph magnification isset in the CPU 201 by the operation of the above-mentioned auto framingmode setting button. That is, in the CPU 201, there are pre-storedphotograph magnifications corresponding to so-called waist shot size inwhich the bust of an object (a person) is contained in the picture planeand so-called full shot size in which the whole body of the object iscontained in the picture plane. When the auto framing mode settingbutton is once depressed, the auto framing mode is set and thephotograph magnification corresponding to the waist shot size is set,and when the auto framing mode setting button is depressed once more,the photograph magnification corresponding to the full shot size is set.When the auto framing mode setting button is depressed once again inthis state, the auto framing mode is released.

During the setting of the auto framing mode, the CPU 201 calculates thefocal length (a first focal length) f of the photographing lens LE onthe basis of the set photograph magnification M and the object distanced from the distance measurement circuit 202, with the half depression ofthe release button, and drives the photographing lens LE so as to assumethis focal length. That is, the photograph magnification M is calculatedby ##EQU1## and therefore, by substituting the photograph magnificationM and the object distance d into equation (1), the focal length f forwhich the set photograph magnification M is obtained can be found.

Also, the CPU 201 calculates a flash reach distance d₁ from the guidenumber GN of the electronic flash device 230 and the full open F-valueof the photographing lens LE when the light emission of the electronicflash device 230 is necessary during the setting of the auto framingmode. Generally, the guide number GN representing the amount of emittedlight of the electronic flash device is given by

    GN=F.sub.NO ×d,                                      (2)

where F_(NO) is the full open F-value indicative of the brightness ofthe photographing lens LE, and in the case of a zoom lens, this fullopen F-value F_(NO) varies in conformity with the focal length. That is,as the focal length becomes greater, the full open F-value F_(NO)becomes darker.

The electronic flash device 230 has its guide number GN set to apredetermined value and accordingly, by substituting this guide numberGN and the full open F-value F_(NO) at any focal length f of thephotographing lens LE into equation (2), the flash reach distance d₁ canbe found. This flash reach distance d₁ is indicative of the objectdistance at which flash photography is possible, and when theabove-mentioned object distance d is greater than the flash reachdistance d₁, even if flash photography is effected, the flash will notsufficiently reach the object and under-exposure will occur.

So, during the setting of the auto framing mode, the CPU 201 changes thefocal length of the photographing lens LE as will be described later ifthe object distance d is greater than the flash reach distance d₁.

The guide number GN shown in equation (2) above is a value when the filmspeed is ISO100, and where a film of any other film speed is used, theguide number GN shown in equation (2) need be multiplied by apredetermined coefficient to thereby effect conversion.

In the construction of the above-described embodiment, the distancemeasurement circuit 202 constitutes object distance detecting means 192,the CPU 201 constitutes full open F-value output means 194 andcalculation means 195 and 295, and the CPU 201 and the motor drivecircuit 204 together constitute lens drive control means 196 and 198.

The procedure of the auto framing photography by the CPU 201 will now bedescribed with reference to the flow chart of FIGS. 21-21B.

This program shows the processing when the switch SW3 is once closedduring the usual photography mode and the auto framing mode by the waistshot size is set, and first, at step S301, whether the half depressionswitch SW1 is closed is judged. If at step S301, the switch SW1 isopened, the program waits until the switch SW1 is closed, and when theswitch SW1 is closed, at step S302, the object distance d is read fromthe distance measurement circuit 202 and brightness information is readfrom the photometry circuit 203. Then, at step S303, whether the lightemission of the electronic flash device is needed is judged on the basisof the read brightness information. If step S303 is negated, advance ismade to step S305, and if step S303 is affirmed, at step S304, acharging start signal is output to the flash control circuit to therebycause this circuit to start charging, and then advance is made to stepS305.

At step S305, whether the read object distance d exceeds 5 m is judged.Here, if the object distance d exceeds 5 m, even if the photographinglens LE is driven to the Tele end (focal length f=32 80 mm), the waistshot size will not be obtained but an object size smaller than that willbe provided. Accordingly, if step S305 is affirmed, at step S306, thefocal length of the driven photographing lens LE is set to 80 mm, and atstep S307, an indication signal is output to the indication circuit 205to turn on LED 221, thereby effecting the indication to the effect thatthe waist shot size is not obtained, and advance is made to step S313.

If step S305 is negated, advance is made to step S308, where whether theobject distance d is less than 1 m is judged. If the object distance dis less than 1 m, even if the photographing lens LE is driven to theWide end (focal length f=35 mm), the waist shot size will not beobtained but an object size larger than that will be provided.Accordingly, if step S308 is affirmed, the focal length f of the drivenphotographing lens LE is set to 35 mm (Wide end) and also, at step S310,the LED 221 is turned on as described above, thereby effecting theindication to the effect that the waist shot size is not obtained, andadvance is made to step S313.

If step S308 is negated, advance is made to step S311, where autoframing calculation is effected. That is, on the basis of the objectdistance d read at step S302 and the photograph magnification Mconforming to the set waist shot size, the focal length f (a first focallength) of the photographing lens LE is calculated by equation (1)above, and then the focal length calculated at step S312 is set as thefocal length of the driven photographing lens LE, and advance is made tostep S313.

At step S313, whether the photography is flash photography using theelectronic flash device 230 is judged, and if the judgment is negative,advance is made to step S319, and if the judgment is affirmative,advance is made to step S314. At step S314, the flash reach distance d₁is calculated from the guide number GN of the electronic flash deviceand the full open F-value F_(NO) conforming to the focal length f set atstep S312, on the basis of equation (2) above. Then, at step S315, theobject distance d read at step S302 is compared with the flash reachdistance d₁. If d≦d₁, advance is made to step S319, and if d>d₁, advanceis made to step S316. At step S316, on the basis of equation (2), thefull open F-value F_(NO) of the photographing lens LE making d=d₁ iscalculated, and the focal length f (a second focal length) having thisfull open F-value F_(NO) is set as the focal length of the drivenphotographing lens LE.

Then, advance is made to step S317, where the object distance d iscompared with a preset reference distance d₀, and if d≦d₀, advance ismade to step S318, and if d>d₀, the photograph magnification becomesmuch smaller than the photograph magnification conforming to the waistshot size set at first and therefore, advance is made to step S324,where LED's 221 and 222 are turned off to thereby terminate theprocessing. That is, in this case, photographing is inhibited.

At step S318, the LED 222 is turned on through the indication circuit205 to thereby effect the indication to the effect that the focal lengthf of the photographing lens LE has been re-set (step S316), and thenadvance is made to step S319. At step S319, a zooming signal is outputto the motor drive circuit 204 to drive the photographing lens LE to thefocal length f set at one of steps S306, S309, S312 and S316. Thereby,the motor drive circuit 204 drives the photographing lens LE to thepredetermined focal length f by the motor 211.

Then, at step S320, whether the full depression switch SW2 is closed isjudged, and if the judgment is negative, advance is made to step S321.At step S321, whether the half depression switch SW1 is closed isjudged, and if the judgment is affirmative, return is made to step S320,and if the judgment is negative, advance is made to step S324. If stepS320 is affirmed, advance is made to step S322, and the exposure controldevice such as the stop and the shutter is driven through the exposurecontrol circuit 207 to effect photographing, and at this time, theelectronic flash device is caused to emit light as required. Thereafter,at step S323, a wind-up signal is output to the motor drive circuit 204,whereby the film is wound up by one frame by the motor 213, and at stepS324, the LED's 221 and 222 are turned off to terminate the processing.

The above-described procedure will be described more specifically.

Let it be assumed that at step S302, for example, the object distanced=4 m is obtained and as a result of the auto framing calculation atstep S311, the focal length (a first focal length) f=70 mm to which thephotographing lens LE should be driven has been obtained. Let it also beassumed that the full open F-value of the photographing lens LE of thiscamera is F_(NO) =7 at the focal length f=70 mm and the guide number ofthe electronic flash device is GN=20. Accordingly, by substituting GN=20and F_(NO) =7 into equation (2), the flash reach distance d₁ =2.86 m isobtained at step S314. At this time, the object distance is d=4 m andtherefore, if photographing is effected at the focal length f=70 mm, anunder-exposed photograph will be taken due to the insufficiency of thequantity of light.

According to the above-described processing procedure, in such a case,step S315 is affirmed and therefore, at step S316, G=20 and d₁ =2.86 aresubstituted into equation (2) to obtain F_(NO) =5, and a second focallength (e.g. f=50 mm) making F_(NO) =5 is newly set. At step S319, thephotographing lens LE is driven to this focal length f. Thereby, thephotograph magnification becomes smaller than the waist shot size set atfirst, but under-exposed photographs are prevented from being taken.

In the foregoing, the description is with respect to the case of autoframing photography, but the present invention is also applicable to anordinary zoom camera which does not have the auto framing mode. That is,when effecting flash photography at any focal length, the flash reachdistance is calculated from the full open F-value of the photographinglens corresponding to this focal length and the guide number of theelectronic flash device, and when the object distance is greater thanthe flash reach distance, a focal length having a full open F-value forwhich the flash reach distance is greater than the object distance maybe set, and the zoom lens may be driven so as to assume this focallength, whereby photographing may be effected.

According to the invention of FIG. 19A, if during flash photography, theobject distance is greater than the flash reach distance, a focal lengthhaving a full open F-value for which the flash reach distance is greaterthan the object distance is set and the zoom lens is driven so as toassume this focal length and therefore, under-exposed photographs areprevented from being taken.

According to the invention of FIG. 19B, if during auto framingphotography (given magnification photography), the object distancedetected when a first focal length is set is greater than the flashreach distance based on the full open F-value conforming to the firstfocal length, a second focal length having a full open F-value for whichthe flash reach distance is greater than the object distance is set andthe zoom lens is driven so as to assume the second focal length andtherefore, even during auto framing photography, under-exposedphotographs are prevented from being taken.

We claim:
 1. A camera comprising:a photographing lens capable ofzooming; a photographing operation member to be manually operated to ahalf depression or a full depression; first operation signal generatingmeans for generating a first operation signal in response to manualoperation of said photographing operation member to a half depression;first zoom signal generating means for generating a first zoom signal inresponse to said first operation signal; zooming means for electricallyzooming said photographing lens in response to said first zoom signaland terminating said zooming when said photographing lens is brought toa predetermined focal length; second operation signal generating meansfor generating a second operation signal in response to manual operationof said photographing operation member to a full depression; andphotographing means for recording a photographing frame formed by saidphotographing lens on a recording medium, in response to said secondoperation signal.
 2. A camera according to claim 1, furthercomprising:manually controlled zoom operation means for generating asecond zoom signal; wherein said zooming means is responsive to saidsecond zoom signal for performing electric zooming of said photographinglens that terminates upon termination of said second zoom signal.
 3. Acamera according to claim 1, wherein said zooming means is adapted tocontinue said zooming once it is started in response to said first zoomsignal, even if manual operation of said photographing operation memberto said half depression is interrupted in the course of said zooming. 4.A camera according to claim 1, wherein said photographing means isnon-responsive to said second operation signal during said zooming bysaid zooming means in response to said first zoom signal.
 5. A cameraaccording to claim 1, wherein:when said second operation signal isgenerated in the course of said zooming by said zooming means inresponse to said first zoom signal, said zooming means immediatelyterminates said zooming; and said photographing means effects saidrecording immediately thereafter in response to said second operationsignal.
 6. A camera according to claim 1, wherein:if said secondoperation signal is generated at the completion of said zooming by saidzooming means in response to said first zoom signal, said photographingmeans effects said recording immediately thereafter in response to saidsecond operation signal.
 7. A camera comprising:a photographing lenscapable of zooming; a photographing operation member to be manuallyoperated; first operation signal generating means for generating a firstoperation signal in response to manual operation of said photographingoperation member; first zoom signal generating means for generating afirst zoom signal in response to said first operation signal; zoomingmeans for electrically zooming said photographing lens in response tosaid first zoom signal and terminating said zooming when saidphotographing lens is brought to a predetermined focal length; secondoperation signal generating means for generating a second operationsignal in response to manual operation of said photographing operationmember; photographing means for recording a photographing frame formedby said photographing lens on a recording medium, in response to saidsecond operation signal; manually controlled zoom operation means forgenerating a second zoom signal; wherein said zooming means isresponsive to said second zoom signal for performing electric zooming ofsaid photographing lens that terminates upon termination of said secondzoom signal; zoom mode setting means for setting one of plural zoommodes including at least first and second zoom modes, wherein, in saidfirst zoom mode, said zooming means responds at least to said first zoomsignal, and, in said second zoom mode, said zooming means isnonresponsive to said first zoom signal but responds to said second zoomsignal; and manually actuated first switching means for generating afirst switching signal; wherein said zoom mode setting means is adaptedto switch between said first and second zoom modes in response to saidfirst switching signal; and wherein said photographing means isresponsive to said second operation signal for recording a photographingframe formed by said photographing lens on a recording mediumirrespective of the zoom mode set by said zoom mode setting means.
 8. Acamera comprising:a photographing lens capable of zooming; aphotographing operation member to be manually operated; first operationsignal generating means for generating a first operation signal inresponse to manual operation of said photographing operation member;first zoom signal generating means for generating a first zoom signal inresponse to said first operation signal; zooming means for electricallyzooming said photographing lens in response to said first zoom signaland terminating said zooming when said photographing lens is brought toa predetermined focal length; second operation signal generating meansfor generating a second operation signal in response to manual operationof said photographing operation member; photographing means forrecording a photographing frame formed by said photographing lens on arecording medium, in response to said second operation signal; manuallycontrolled zoom operation means for generating a second zoom signal;wherein said zooming means is responsive to said second zoom signal forperforming electric zooming of said photographing lens that terminatesupon termination of said second zoom signal; zoom mode setting means forsetting one of plural zoom modes including at least first and secondzoom modes, wherein, in said first zoom mode, said zooming meansresponds at least to said first zoom signal, and, in said second zoommode, said zooming means is nonresponsive to said first zoom signal butresponds to said second zoom signal; manually actuated first switchingmeans for generating a first switching signal; wherein said zoom modesetting means is adapted to switch between said first and second zoommodes in response to said first switching signal; and wherein: saidzooming means also responds to said second zoom signal when said firstzoom mode is set; said camera further comprises second switching meansfor generating a second switching signal when said second zoom signal isgenerated while said first zoom mode is set; and said zoom mode settingmeans is adapted to switch from said first zoom mode to said second zoommode in response to said second switching signal and to prohibit theresponse of said zooming means to the first operation signal if it isgenerated thereafter.
 9. A camera according to claim 8, wherein, if saidfirst switching signal is generated after the switching from said firstzoom mode to said second zoom mode in response to said second switchingsignal, said zoom mode setting means is adapted to switch from saidsecond zoom mode to said first zoom mode.
 10. A camera according toclaim 8, further comprising:third switching means for generating a thirdswitching signal when said second operation signal is generated afterthe switching from the first zoom mode to the second zoom mode inresponse to said second switching signal, wherein said zoom mode settingmeans is adapted to switch from the second zoom mode to the first zoommode in response to said third switching signal.
 11. A camera accordingto claim 8, further comprising:further switching means for generating afurther switching signal when said photographing means is operated afterthe switching from the first zoom mode to the second zoom mode inresponse to said second switching signal, wherein said zoom mode settingmeans is adapted to switch from the second zoom mode to the first zoommode in response to said further switching signal.
 12. A cameraaccording to claim 11, further comprising:further switching means forgenerating a further switching signal when said photographing means isoperated after the switching from the first zoom mode to the second zoommode in response to said second switching signal, wherein said zoom modesetting means is adapted to switch from the second zoom mode to thefirst zoom mode in response to said further switching signal.
 13. Acamera comprising:a photographing lens capable of zooming; aphotographing operation member to be manually operated; first operationsignal generating means for generating a first operation signal inresponse to manual operation of said photographing operation member;first zoom signal generating means for generating a first zoom signal inresponse to said first operation signal; zooming means for electricallyzooming said photographing lens in response to said first zoom signaland terminating said zooming when said photographing lens is brought toa predetermined focal length; second operation signal generating meansfor generating a second operation signal in response to manual operationof said photographing operation member; photographing means forrecording a photographing frame formed by said photographing lens on arecording medium, in response to said second operation signal; objectdistance detecting means for generating an object distance signalcorresponding to the distance to an object to be photographed; and focallength setting means for setting said predetermined focal length,according to said object distance signal, so that the size of saidobject becomes substantially constant with respect to the photographingframe regardless of the object distance; wherein said zooming meanseffects the zooming of said photographing lens to the set predeterminedfocal length in response to said first zoom signal.
 14. A cameraaccording to claim 13, wherein:said object distance detecting means isadapted to detect said object distance in response to said firstoperation signal.
 15. A camera comprising:a photographing lens capableof zooming; a photographing operation member to be manually operated;first operation signal generating means for generating a first operationsignal in response to manual operation of said photographing operationmember; first zoom signal generating means for generating a first zoomsignal in response to said first operation signal; zooming means forelectrically zooming said photographing lens in response to said firstzoom signal and terminating said zooming when said photographing lens isbrought to a predetermined focal length; second operation signalgenerating means for generating a second operation signal in response tomanual operation of said photographing operation member; andphotographing means for recording a photographing frame formed by saidphotographing lens on a recording medium, in response to said secondoperation signal; object distance detecting means for generating anobject distance signal corresponding to the distance to an object to bephotographed in response to said first operation signal; focal lengthsetting means for setting said predetermined focal length, according tosaid object distance signal, so that the size of said object withrespect to the photographing frame becomes substantially constantregardless of the object distance; wherein said zooming means is adaptedto effect zooming of said photographing lens to the set predeterminedfocal length in response to said first zoom signal; wherein said objectdistance detecting means generates an object distance signal again afterthe completion of zooming in response to said first zoom signal andbefore the start of recording by said photographing means; and focusingmeans for focusing said photographing lens according to thelast-mentioned object distance signal.
 16. A camera comprising:aphotographing lens capable of zooming; a photographing operation memberto be manually operated; first operation signal generating means forgenerating a first operation signal in response to manual operation ofsaid photographing operation member; first zoom signal generating meansfor generating a first zoom signal in response to said first operationsignal; zooming means for electrically zooming said photographing lensin response to said first zoom signal and terminating said zooming whensaid photographing lens is brought to a predetermined focal length;second operation signal generating means for generating a secondoperation signal in response to manual operation of said photographingoperation member; photographing means for recording a photographingframe formed by said photographing lens on a recording medium, inresponse to said second operation signal; and manually controlled zoomoperation means for generating a second zoom signal; wherein saidzooming means is responsive to said second zoom signal for performingelectric zooming of said photographing lens that terminates upontermination of said second zoom signal; and wherein: if said second zoomsignal is generated in the course of said zooming by said zooming meansin response to said first zoom signal, said zooming means is adapted toimmediately interrupt said zooming; and said zooming means is adapted toeffect said zooming in response to said second zoom signal immediatelythereafter.
 17. A camera comprising:a photographing lens capable ofzooming; a photographing operation member to be manually operated; firstoperation signal generating means for generating a first operationsignal in response to manual operation of said photographing operationmember; object distance detecting means for generating an objectdistance signal corresponding to the distance to an object to bephotographed, in response to said first operation signal; focal lengthsetting means for setting the focal length of said lens, according tosaid object distance signal, so that the size of said object withrespect to a photographing frame formed by said photographing lensbecomes substantially constant regardless of the object distance; firstzoom signal generating means for generating a first zoom signal inresponse to said first operation signal; manually controlled zoomoperation means for generating a second zoom signal; zooming means forelectrically zooming said photographing lens in response to said firstzoom signal and terminating said zooming when said photographing lens isbrought to the focal length set by said focal length setting means,wherein said zooming means is responsive to said second zoom signal forperforming electric zooming of said photographing lens that terminatesupon termination of said second zoom signal; zoom mode setting means forsetting one of plural zoom modes including at least first and secondzoom modes, wherein, in said first zoom mode, said zooming meansresponds to said first and second zoom signals, and, in said second zoommode, said zooming means is non-responsive to said first zoom signal butresponds to said second zoom signal; manually actuated first switchingmeans for generating a first switching signal, wherein said zoom modesetting means is adapted to switch between said first and second zoommodes in response to said first switching signal; second switching meansfor generating a second switching signal if said second zoom signal isgenerated while said first zoom mode is set, wherein said zoom modesetting means is adapted to switch from said first zoom mode to thesecond zoom mode in response to said second switching signal and toprohibit the response of said zooming means to said first operationsignal which may be generated thereafter; second operation signalgenerating means for generating a second operation signal in response tomanual operation of said photographing operation member; andphotographing means for recording the photographing frame formed by saidphotographing lens, in response to said second operation signal.
 18. Acamera according to claim 17, wherein:if said first switching signal isgenerated after the switching from said first zoom mode to said secondzoom mode by said second switching signal, said zoom mode setting meansis adapted to switch from said second zoom mode to said first zoom mode.19. A camera according to claim 18, further comprising:third switchingmeans for generating a third switching signal when said second operationsignal is generated after the switching from the first zoom mode to thesecond zoom mode in response to said second switching signal, whereinsaid zoom mode setting means is adapted to switch from the second zoommode to the first zoom mode in response to said third switching signal.20. A photographing method for a camera provided with a zoom lens,comprising, in succession, the following steps:(a) electrically zoomingsaid zoom lens to a predetermined focal length by manual actuation of aphotographing operation control member, without performing aphotographing operation; (b) electrically zooming said zoom lens, set atsaid predetermined focal length, by manual actuation of a zoomingoperation control member; (c) prohibiting, in response to step (b),repetition of step (a); and (d) effecting a photographing operation bymanual actuation of said photographing operation control member.
 21. Aphotographing method for a camera provided with a zoom lens, comprising,in succession, the following steps:(a) detecting an object distance inresponse to manual actuation of a photographing operation controlmember, without performing a photographing operation; (b) selecting afocal length at which said zoom lens is to be set, according to thedetected object distance; (c) electrically zooming said zoom lens to theselected focal length; (d) electrically zooming said zoom lens, set atsaid selected focal length, by manual actuation of a zooming operationcontrol member; (e) prohibiting, in response to step (d), repetition ofstep (c); and (f) effecting a photographing operation by manualactuation of said photographing operation control member.
 22. A cameracomprising:a photographing lens which is movable and is capable ofvarying the state of a photographing frame formed by said lens, by saidmovement; a photographing operation member to be manually operated;first operation signal generating means for generating a first operationsignal in response to manual operation of said photographing operationmember; object distance detecting means for generating an objectdistance signal corresponding to the distance to an object to bephotographed, in response to said first operation signal; lens positiondetermining means for determining the position of said photographinglens at a next photographing operation according to said object distancesignal; first lens drive signal generating means for generating a firstlens drive signal in response to said first operation signal; manuallyoperable second lens drive signal generating means for generating asecond lens drive signal for the duration of a manual operation thereof;lens driving means for electrically driving said photographing lens inresponse to said first lens drive signal and terminating said drivingwhen said photographing lens reaches the position determined by saidlens position determining means, wherein said lens driving means isadapted to effect electrical driving of said photographing lens duringsaid second lens drive signal and to terminate such driving when thegeneration of said second lens drive signal is terminated; lens drivemode setting means for selecting one of plural lens drive modes whichinclude at least first and second lens drive modes, wherein, in saidfirst lens drive mode, said lens drive means responds to said first andsecond lens drive signals, and, in said second lens drive mode, saidlens drive means is nonresponsive to said first lens drive signal butresponds to said second lens drive signal; first switching means forgenerating a first switching signal in response to a manual operation,wherein said lens drive mode setting means is adapted to switch betweensaid first and second lens drive modes in response to said firstswitching signal; second switching means for generating a secondswitching signal when said second lens drive signal is generated whilesaid first lens drive mode is set, wherein said lens drive mode settingmeans is adapted to switch from said first lens drive mode to saidsecond lens drive mode in response to said second switching signal andto prohibit the response of said lens drive means to said firstoperation signal which may be generated thereafter; second operationsignal generating means for generating a second operation signal inresponse to manual operation of said photographing operation member; andphotographing means for recording the photographing frame formed by saidphotographing lens, in response to said second operation signal.
 23. Acamera according to claim 22, wherein said lens driving means drives thephotographing lens for zooming.
 24. A camera comprising:a photographinglens capable of zooming; a photographing operation member to be operatedby a manual operation that includes a first manual operation part and asecond manual operation part conducted after said first manual operationpart; first operation signal generating means for generating a firstoperation signal in response to said first manual operation part; lightmetering means for generating a brightness signal corresponding to thebrightness of an object, in response to said first operation signal;focal length setting means for generating a focal length signalcorresponding to a focal length to be assumed by said photographing lensat a next photographing operation, in response to said first operationsignal; flash requirement discriminating means for discriminatingwhether a flash emission is needed at the next photographing operation,based on said brightness signal and said focal length signal, andgenerating a flash needed signal if the flash emission is needed;charging completion detecting means for detecting, in response to saidflash needed signal, whether the charging of a capacitor for flashemission has been completed, and generating a charging uncompletedsignal if said charging is not yet completed; display means forproviding a display in response to said charging uncompleted signal;first zoom signal generating means for generating a first zoom signalafter the discrimination by said flash requirement discriminating means,or, if said charging uncompleted signal is generated, after the displayby said display means; zooming means for electrically zooming saidphotographing lens in response to said first zoom signal, andterminating said zooming when said photographing lens is brought to thefocal length to be assumed at the next photographing operation; secondoperation signal generating means for generating a second operationsignal in response to said second manual operation part of saidphotographing operation member; and photographing means for recording aphotographing frame formed by said photographing lens, on a recordingmedium, in response to said second operation signal.
 25. A cameraaccording to claim 24, further comprising:charging means for startingthe charging of said capacitor in response to said charge uncompletedsignal, said charging being continued even during the zooming by saidzooming means.